ANTUMBRA TUNE User manual

ANTUMBRA
TUNE
MANUAL

TABLE OF CONTENTS
01. INSTALLATION 4
02. JACK LIGHTS 5
03. FRONT 6
04. DISPLAY MODES 7
05. RELATIVE MODE 8
06. STROBE MODE 9
07. OUTPUT MODE 10
08. SCALE SELECTION 11
09. VU METER 12
10. SAVING 13
11. NOTE AND OCTAVE VIEW 14
12. “SCREENSAVER” MODE 15
13. ERROR DISPLAY 16
14. ACCURACY 17
15. SOFTWARE MODIFICATIONS 18

00. THANK YOU!
Thank you for purchasing the Antumbra TUNE module!
In this documentation you can find information about the
installation and use of the module.

01. INSTALLATION
POWER CABLE HEADER: Red stripe should be on the top,
next to the white marker!
When you turn TUNE on the side, you should see the mod-
ule as it is on the left illustration. Plug in the power cable
to the power cable header pins, but BE CAREFUL with the
orientation of the cable! The RED STRIPE should be to-
wards the TOP of the module, indicated by the white line
above the header pins. By doing otherwise you can poten-
tially harm the module or even your whole system! Power
off your eurorack system and connect the other end of
the cable to the power source, here also pay attention to
the PSU manufacturer’s instructions!
SN74HC595 SN74HC595
ATMEGA328P-AU
DG419
TL072
16.000
103
103
103
493
104104

02. JACK LIGHTS
On the back there is a jumper for enabling the jack lights.
Note that by enabling them the module draws additional
current from the 12V rail.
Jack lights jumper
SN74HC595 SN74HC595
ATMEGA328P-AU
DG419
TL072
16.000
103
103
103
493
104104

03. FRONT
1 Display LEDs
2 Mode button
3 Input jack
4 Output jack
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5
2
3
4
1

04. DISPLAY MODES
Connect the output of your VCO to the TUNE input.
Press the button for 1 second, release it when either the
LED marked with 0 or - starts to blink. Now you are in dis-
play mode selection. Press the button to toggle between
the two modes. See the next pages for their description.
When the LED marked with - is blinking you are in rela-
tive mode.
When the LED marked with 0 is blinking you are in strobe
mode.
Press the button again for 1 sec to exit display mode se-
lection.
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5

05. RELATIVE MODE
In this mode the current nearest note blinks fast, and
above or below 1-3 LEDs are lit if the VCO frequency is
out of tune. If the VCO frequency is higher than the cur-
rent nearest notes LEDs are lit above, if it’s lower they are
lit below. Adjust the VCO frequency till the LEDs around
the blinking note are off and when the blinking LED turns
solid you are in tune.
The current note value is written on the left of the LED.
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5
FREQ FREQ

06. STROBE MODE
In this mode the current nearest note blinks fast and is
bright, an other dimmer LED is going up or down if the VCO
is out of tune. The speed of the wandering LED indicates
the distance from the nearest note, and it’s direction dis-
plays which way the VCO has to be tuned. The closer the
VCO frequency is to the nearest note, the slower the LED
is. If the VCO frequency is higher than the nearest note,
the LED goes downwards, if it’s lower it goes up. Adjust
the VCO frequency till the second LED stops.
The current note value is written on the left of the LED.
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5
FREQ FREQ

07. OUTPUT MODE
Press and hold the button for 2 seconds till the LEDs
marked SUB or TRU are blinking, now release it.
Press the button to toggle between the two modes.
When the LED marked SUB is blinking the output jack pro-
duces a square wave one octave below the input frequen-
cy.
When the LED marked TRU is blinking, the input is fed to
the output unmodified.
Press the button again for 1 sec to exit display mode se-
lection.
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5

08. SCALE SELECTION
Press and hold the button for 3 seconds till the LEDs
marked 432 or 440 are blinking, now release it.
Press the button to toggle between the two modes.
The tuning mode changes the scale the module tunes to,
select between A432Hz and A440Hz tuning modes.
Press the button again for 1 sec to exit display mode se-
lection.
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5

09. VU METER
Press and hold the button for 4 seconds till the LEDs are
not blinking anymore.
Press the button to toggle between 0-5V and +/-5V
modes.
In 0-5V mode, the input signal is split once from -5-0V
and once 0-5V, then the absolute larger is chosen. Each
LED represents about 0,4V.
In +/-5V mode LEDs 0-5 represent -5-0V, LEDs 6-12 rep-
resent 0-5V. Each LED corresponds to about 0.8V.
In both mode the peak is held for 1sec.
To exit this mode press the button for 1sec.
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5

10. SAVING
The module saves it’s current state automatically each
time you exit the menu so that it can recover your pref-
erences on power cycles.

11. NOTE AND OCTAVE VIEW
When you are not in the menu, press the button quickly
to switch between note and octave view.
Note display depends on the mode selection described
previously.
Octave is displayed by a slowly blinking LED, the octave
number is written on the right side of the LED, it goes
from -1 to 6 octaves.
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5
read:
F#2

12. “SCREENSAVER” MODE
Once you start modulating your VCO, TUNE can go hectic
trying to display the current note, to enter “screensaver”
mode press the button twice quickly, now it shows that
it’s in this mode by a single pulsating LED. To exit this
mode press the button once quickly.
C
#
D
E
#
F
G
#
#
A
#
B
440432TRUSUB
0
1
3
2
4
6
5

13. ERROR DISPLAY
If there’s no jack present on the input no LEDs should be
lit. If there is signal present but it’s level is too low, two
LEDs going up and down from the middle start running.
Increase the level till you reach the threshold and the
module displays the current note.

14. ACCURACY
The signal fed to TUNE is turned into a square wave and is
divided by two (sub output) to increase measurement ac-
curacy in higher frequencies. The measurement accuracy
should be between +/- 3 cents.
TUNE works best with simpler/repeating waveforms, it
could have a hard time measuring the frequency of chords,
complex and modulated waveforms.
Threshold level
Input signal
Input signal transformed to square
Optimal waveform for measurement
Not optimal waveform for measurement

15. SOFTWARE MODIFICATIONS
Feel free to modify the software of your module, but at
your own risk! Antumbra doesn’t take responsibility for
damaged microcontrollers, if you proceed from here I as-
sume you know what you are doing.
If you are unsure of what you are doing, please contact
Antumbra in email at [e-mail]!
Use the 6 pin SPI header on the back to upload code to the
module. You will need an AVR programmer for this.
Pin 1 is marked by a dot below the header.
SPI header
SN74HC595 SN74HC595
ATMEGA328P-AU
DG419
TL072
16.000
103
103
103
493
104104

TUNE is designed by David Szebenyi under Antumbra.
www.antumbra.eu
Manual by David Szebenyi (www.aman.hu)
2020 • All rights reserved!